1421221721 has 2 divisors, whose sum is σ = 1421221722. Its totient is φ = 1421221720.

The previous prime is 1421221693. The next prime is 1421221723. The reversal of 1421221721 is 1271221241.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1088670025 + 332551696 = 32995^2 + 18236^2 .

It is an emirp because it is prime and its reverse (1271221241) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1421221721 - 2⁶ = 1421221657 is a prime.

Together with 1421221723, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (1421221723) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 710610860 + 710610861.

It is an arithmetic number, because the mean of its divisors is an integer number (710610861).

Almost surely, 2^1421221721 is an apocalyptic number.

It is an amenable number.

1421221721 is a deficient number, since it is larger than the sum of its proper divisors (1).

1421221721 is an equidigital number, since it uses as much as digits as its factorization.

1421221721 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 448, while the sum is 23.

The square root of 1421221721 is about 37699.0944320948. The cubic root of 1421221721 is about 1124.3131203916.

Adding to 1421221721 its reverse (1271221241), we get a palindrome (2692442962).

The spelling of 1421221721 in words is "one billion, four hundred twenty-one million, two hundred twenty-one thousand, seven hundred twenty-one".